As more and more intelligent downhole equipment are used in the harsh oil field environment such as high temperature and high pressure conditions, establishing an efficient way to activate a downhole device becomes more and more valuable. An electro-mechanical actuator, such as a solenoid, needs to be activated with significant amount of electrical power. Moreover, if the electro-mechanical actuator needs to hold a position, a significant amount of power is used to maintain the electric field.
In downhole equipment, differential pressure may be needed to move pistons that operate valves, set packers and plugs for example. This differential pressure can be obtained by an atmospheric chamber and controlling the annulus hydrostatic pressure to be ported into the atmospheric chamber. When hydrostatic pressure becomes extreme (e.g., above 20,000 psi), the atmospheric chamber creates extreme pressure differentials across seals and pressure containing materials. A method of reducing and controlling the differential pressure is to develop differential pressure via an electrical pump. Again, a significant amount of power is necessary to keep the pump operating. However, the downhole electrical power capacity is limited in the harsh environment.